Add parsing for attributes and attibutes on operations.  Add IR representation
for attributes on operations.  Split Operation out from OperationInst so it
can be shared with OperationStmt one day.

PiperOrigin-RevId: 203325366
diff --git a/lib/IR/AsmPrinter.cpp b/lib/IR/AsmPrinter.cpp
index b24eb2f..1cefc0a 100644
--- a/lib/IR/AsmPrinter.cpp
+++ b/lib/IR/AsmPrinter.cpp
@@ -22,6 +22,7 @@
 
 #include "mlir/IR/AffineExpr.h"
 #include "mlir/IR/AffineMap.h"
+#include "mlir/IR/Attributes.h"
 #include "mlir/IR/CFGFunction.h"
 #include "mlir/IR/MLFunction.h"
 #include "mlir/IR/Module.h"
@@ -32,6 +33,14 @@
 using namespace mlir;
 
 
+void Identifier::print(raw_ostream &os) const {
+  os << str();
+}
+
+void Identifier::dump() const {
+  print(llvm::errs());
+}
+
 //===----------------------------------------------------------------------===//
 // Function printing
 //===----------------------------------------------------------------------===//
@@ -140,7 +149,18 @@
 
 void CFGFunctionState::print(const OperationInst *inst) {
   // TODO: escape name if necessary.
-  os << "  \"" << inst->getName().str() << "\"()\n";
+  os << "  \"" << inst->getName().str() << "\"()";
+
+  auto attrs = inst->getAttrs();
+  if (!attrs.empty()) {
+    os << '{';
+    interleave(attrs, [&](NamedAttribute attr) {
+      os << attr.first << ": " << *attr.second;
+    }, [&]() { os << ", "; });
+    os << '}';
+  }
+
+  os << '\n';
 }
 
 void CFGFunctionState::print(const BranchInst *inst) {